Assig-nobs



W. J. MURDOCK ET AL PROCESS FOR muumc'runm 0F COMBUSTIBLE cms FiledSept. 23. 1924 Patented Get. 5, 1926.

tetra WILLIS J. ivmnnooigor AURORA, ANn EDGAR n. LUNGREN, onJoLIn'r,ILLINOIS, AND OWEN B. EVANS, or PHILADELPHIA, PENNSYLVANIA, ASSIGNORS,BY MESNE AS- SIGNMENTS, T0 PIER rnoonss oonrone'riomor AURORA, ILLINOIS,A conroRATIoN or ILLINOIS.

PnooESS roe. MA UrAorUnn or ooMBUSrIBLn GAS.

; Application filed. September ZS, 1924. Serial No. 739;282.;

This invention relates to improvements in process for manufa'ctureofcombustible g In the manufacture of combustible gas, such as blue orcarbureted water gas, or. producer gas, from solid fuel, one of the mainoperations is the'blasting which takes place in the generator, which thebed of fuel is gradually and progressively reduced and heated toincandescen'ce in order to permit the necessary, chemical reactionstaking place'in the generator. 7

Gas generating fuels as received at the gas producer are ordinarilycomposed of mixed sizes, and as the fuel is charged into the usualcylindrical generator, it is a well known fact that the finer or smallerparticles of the fuel, sometimes referred to as the lines, tend toconcentrate in the center of the generator, and the larger or coarserparticles tend to gravitate or. roll towards the confining walls, thatis, there is a natural tendencyof solid fuels to more or less segregateinto an outer mass of larger or coarser particles, and an inner orcentral core or mass of finer or smaller particles. Furthermore, whenthe fuel is charged into the generator from the top, as customary,

there is a natural tendency of the fuel to crown at the center on thetop of'the fuel bed.

the fuel in the generator is permitted to follow its normal course inthe manneri ndicated in the preceding paragraph, there is a verynoticeable variation in the degrees of permeability of the fuel bed tothepassage of air orsteam, or air and steam blasts.

up through the supporting grate and through the fuel bed, or in thereverse direction, the outer portion of the mass adjacent the retainingwalls of the generator offering a very much less resistance to thepassage of,

ofthe fuel bed becomes what is known as an inactivear'ea. v

As the fuel is consumed in an ordinary generator of circular crosssection, and new charges added the entire mass descends gradually andslowly to the grate. When a fuel low in volatile matter is used, such asanthracite coal or coke, it passes from the upper zone of what is calledgreen or comparatively cold fuel to the next lower zone of incandescentfuel during the distillation, carbonization and processing thereof, andfinally from theincandescent zone down to the last zone of spent fuel orashes resting upon'the grate. When fuel high in vol atile matter isused,such as bituminous coal, therefis an additional zone, commonly calledthe plastic zone, which forms above the incandescent zone due to thedriving off. of the larger amounts of volatile matter therefrom in thedistillation and processing thereof to the cokefco'ndition necessary to.obtain a water gas reaction. During this'gradual descent of the fuelthrough the generator, the outer portions of the fuel, in contact withor closely adjacent to the retaining walls of the generator, areappreciably retarded in their movements because of the friction betweenthose portions of the fuel and the walls, whereas the center portion ofthe mass of fuel is free to settle Experience has demonstrated thatwhere more quickly, thus producing a differential settling action, whichfurther tends to compact or solidify the center portion of the fuel andloosenor,render-more permeable the outer peripheral pcrtions of thefuel. settling action described further tends to increase the differencein permeability to the blasts of air and steam between that of theoutermost portions and that of the center portions of the fuel bed.

Another factor still further tending to increase the difference inpermeability between the outermost portions, and the inner portions ofthe fuel bed, when bituminous coal is used in the generator, is thatwhich results from the formationunder heat, of the olastic zone referredto which durin the progression of combustion envelope the central inertmass, so as to completely out off the same from blasting andCt'tll'JOlllZEltlCiIh This condition is due to the difference inpermeability referred to, causing a distinct and well known tendency ofthe air, when introduced below the grate, to select a passage up throughthe generator between the refractory. 'wall and the fuel itself, ratherthan throughthe body of the fuel, resulting in much .more rapidcombustion and higher temperatures being evolved in this portion of thefire. This condition is observable in connection with all kinds ofgenerator fuels, but in the case of a softcoal fire is accentuatedbecause there is a shrinkage of the .fuel away from the refractory wallOf h generator duringthe process of carbonization, giv ng a still freerpas-sage to theair.

The high. degree of heat, which is thus evolved about'the periphery of.the fire progresses through the bed of fuel horizontal- 1y relatively tothe refractory walls "of the generator, and to a known limited distancefrom such walls, and this portion of the fuel rapidly reaches astate ofincandescence during the blast, ready for the water gas reaction, for ahorizontal width of only from 18 to ijinches inwardly from the wall ofthe generator, which is an appreciable distance from the center thereof.This action causes the formation, during the various stages of aroression of the active ortion of the fuel of the sticky plastic zone ofpartially coked fuel immediately in advance of the incan;

descent area throughout its extent, and since such area extends inwardlyfrom the wall of the generator only approximately from 18 to 24 inches,the plastic formation complete "ly surrounds the inner mass ofthe fuelbed.

. some of the foregoing factors normally tending to take place in agenerator of the usual character with the usual method of' manufacturewhere the entiremass of fuel is supported on a grate of the usualcharacter, is to produce an outer mass-or area,

which is relatively very active and subject 'to rapid combustion, and aninner central portion or mass which is inactive and in which little orno .combustion takes place. Furthermore, where a very active areaisdeveloped, so-called weak spots are produced in those portions of thefuel bed withthe result that channelling ensues, thus permitting arelatively excessive flow of air in and adjacent the channels, morerapid burning or consumption of the adjacent fuel, and an increased flowof air, steam and gas. In such condition of unstable equilibrium,

and may, and often does, reacha point such that all the blast ispractically concentratedin one path through th-ebody of fuel and this,in turn, permits the blast to assume avery high velocity in its passagethrough the fuel and to carry with it portions Of SQllCl fuel over intothe fixing chamber, thus causmg frequent clogging of the latter,andnecessitating shutting down to cleani it out, with consequent loss oftime and use of the apparatus.

The foregoing condition occurs with all solid generatingfuels ingeneral, and is particularly accentuated when bituminous coal is used,due t'o' itsimmobile and sticky character when partially coked, causingit to form theplastic zone which is not only impervious to blasting asbefore stated, but 'will'not of itself, fill] theholes or channels whichmay be formed, and it' 'becomesnecessary tobar the fuel bed frequent-ly.g

Objects of our invention, therefore, are

to provide .improvementsin the'proc'essof j manufacturing a combustiblegas from sol id fuel, which will obviate the disadvantageous conditionshereinbefore described, to so carry out the action in the generator asto insure a bed of fuel of practically-or substantially uniform blastproducts and render the entire body substantially uniformly active; toincrease the activated area of the fuel bed; to eliminate the formationof the inactive 013 more or less impermeable portions of thefuel bed;and, in general, to materially increase-the efpermeability to theficiency and economy of operation of the steps of the process inthegenerator neces sary in the manufacture of a combustible gas.

ominvention, considered from some of its broader aspects, consists in sodisposing or dispersing the conglomerate mass of solid fuel as itischarged into the generator and in its passage'through the generator,that every portion of the fuel'bed will be within an active-a1'ea withrespect to a radiating wall of the generatoryin preventing theinitiation of the formation of acompacted relatively impermeable portionat any point fuel bed; in cooling such'body to prevent injury theretofrom excessive heat; in so distributing the fuel while subjected toaction in the generator that the distance between any twowallstransv'ersely of thcfu-el bed does not exceed twice thewidth of theknown or determinable active area of the the channeling action becomesprogressive fuel with respect to a wall; and in permitarrangedasindicated in the preceding.

- in Fig. 1.

the fuel bed through the grate with uniformity throughout the gratesupported area of the. fuel while the body of the fuel is in thedrawings forming a part of specification,.Fig. 1 illustrates a more orless diagrammatic view indicating a vertical, diametrical section of ageneratorof cylindrical form adapted for the carrying out of ourimproved process, andFig. 2 is a transgenerator shown verse sectionalview of the In said drawing, the-generator proper is indicated at 2, thesame preferably being of cylindrical formation as generally employed,and preferably lined on the interior of the outer confining wall withrefractory material. Said generator is preferably provided with ahorizontally extended grate 8, which 'may be of usual. construction anddisposed above the bottom of the generator proper so as to leave an ashpit 42 from which some of the ashes may be removed through a suitableash pit door 5. Clinker doors of any desirable constructionareindicatedconventionally at 6. As customary in a generator of this character forproducing carbureted water gas, the generator is provided with anofftalre passage 7, near'the top, the gases being conducted through asuitable pipe 8 having the usual v interconnected valves 9 and 10. Thefuel, as customary, is charged a through the top opening 11;

For the purpose of carrying out our invention, in one manner, in thetype of generator shown we provide a centrally disposed pier or coneindicated broadly by the reference character A, said pier or cone Apreferably being of circular cross section and disposed centrally of,and supported upon the'grate 3. Such pier may be of any desiredconstruction, that is, either hollow or solid, or of a' suitable builtup construction where intended for application to a generator already'inuse, and is preferably composed of suitable refractory material. Thetopmost portion of the pier is preferably cone' shaped, as indicated at12, so as to facilitate the uniform distribution of the fuel all aroundthe generator as the fuel is charged through the top opening 11. In

'actual practice, and this is an important zone of the fuel, andpreferably substantially level with the offtake opening 7. In thismanner, the beginning or'initiation of the formation of a centralinactive cone in the body of the fuel at any stage of distilla-' tion,carbomzation or processing thereof is prevented. Furthermore the amountof lines in the fuelwhich would normally tend this pier A, will bedistributed in an annulus of much greater radius, and thoroughlyinter-mingle with the larger portions of the conglomerate mass of fuel.

Although the pier A may be of any solid construction if desirechit ispreferably provided with an interior chamber 13, extending from thebottom of the pier to a point adjacent the top thereof, which chamber ispreferably utilized for the introductionof means forsuitably cooling thepier, so as to prevent overheating thereof and possible deteriorationdue to this cause. This is accomplished by providing the combined steamand air blasting conduit 14 which extends into the ash pit l a suitabledistance, with an angular extension 15, which projects upupper portionof the generator for blasting the fuel body in a reverse direcuion, ordownwardly, in a well known manner.

From the preceding description, considered in connection with thedrawing, it will be observed that the blasts have equal and uniformaccessibility to the bottom of the fuel through all portions of thegrate, thus insuring uniform admission of the blasts to thebody of thefuel. By proportioning the generator so that the distance between theopposed wall surfaces of the generator and the pier is at no point morethan twice the' known width of the active area of the fuel with respectto a retaining wall, all portions of the fu'elare necessarily arrangedwithin such active area with'respect to such walls through the entiremass of fuel from top to bottom. Furthermore, not only are allportionsof the fuel located within an active radiating area of aretaining or confining wall, but, in addition, the extension of thecentral pier well up into the loose or green fuel zone to a pointsubstantially on a level with the offtake, prevents the initiation orformation of any centrally disposed, inert or inactive or impermeablecore or mass with the result that the body of fuel, as it gravitatesdown through the enerator from the loose or green fuel zone to theincandescent zone, is distilled and processed uniformly throughout thecross-sectional areas of the body offuel.

A common size for a generator of circular cross section with a bottomsuch as indicated in the drawing and hereinbefoii'e described, used inthe manufacture of carbureted water gas, is one having an inside.

diameter of 9 feet. With such a generator,

usingbituminous coal as the generating fuel,

we have found from actual experience, that very efficientresults areobtained with our invention where a pier or cone, such as shown inFigure 1 of refractory material is employed of 3 feet outside diameter,centrally disposed on the grate as indicated in the drawing. With suchan arrangement, it will be observed that there is no portion of the fuelbed which is more than 18 inches from any radiating wall of thegenerator,-

and further, that the blasts of air and steam are over the entiregrate-supported area of the fuel bed with equal facility andaction atallpoints, thus assuring uniformity of combustion within the entire bodyof the fuel. Actual practice has demonstrated 7 that, where air andsteam blasts are pernation of the two.

mitted to enter the body of the fuel through the grate with relativeuniformity throughout the entire area supported by the grate,

that active zones will be formed within a distance of about 18 to 24inches of any refractory wall, this active zone being assured by thepassage of preheated gases through the fuel or by radiation from theheated refractory surfaces, or by a combi- Consequently, it will beobserved that by the use of our invention, all portions of the fuelarebrought within an assured active zone of substantially uniformpermeability and uniform rate of com-.

bu stion.

By way of comparison, we have found,

that the best results obtainable under the prior common practice with acarbureted water gas set, using bituminous coal, the

generator of which was 9 feet internal diameter, was by blasting at therate of 5,000 cubic feet of air perminute, with a resulting capacity ofapproximately 1,500,000 cubic feet of gas perQ l hours, whereas, by

' the addition of a pier such as we have shown and described of 3 feetoutside diameter,

thecapacity was increased to2,500,000 cubic feetof per 2 f hours, theamount of fuel blown over into the fixing chamber was decreasedapproximately the amount of fuel required per 1,000 feet of gas wasdecreased approximately 8 lbs. and the amount ofclinlrers formed wasmaterially decreased. By way of a rough approximation, it may be statedthat in the generator used without any pier, the active area is that ofthe annulus having an outside diameter of 9 feet and an inside diameterof 6 feet (that is, 9

feet less two times 18 inches) or approXi-.

mately 35.3 sq. ft., whereas, by the introduction of the pier of 3 feet,outside diameter, the active area was increased to that within theannulus having a 9 foot outside diam star and a 3 foot inside diameter,or approx imately 56.6 sq. ft. that is, an increase of approximately inthe active area, and an increase of approximately 67% in the capacity.

We havelier-ein illustrated'one apparatuspartlcularly suitable forcarrying out our improved process and have described" the process withparticularity in connection with the apparatusdisclosed. As will beunderstood by' those skilledin the art, all changes and modificationsthat come within the scope of the claims appended hereto, 7

are contemplated. Claims to the apparatus herein illustrated anddescribed are reserved to form the subject matter of a separatedivisional application.

o claim: 1. The herein described improvement in the manufacture of acombustible gas from' coal of relatively high volatile content, whichincludes: disposing the fuel inan annular column and confining the same;between inner and outer refractory walls with all portions of the fuelof the annular column within an effective radiating distance of therefractory walls and thereby preventing the formation of an impermeablemass or core in the fuel; and blasting the column of fuel in averticaldirection substantially uniformlythroughout-the area of theannular column of fuel with air and steam alternately.

2. The herein described improvement in the manufacture of a combustiblegas from coal, and wherein the body of fuel gravitates through thegenerator, which consists in:

passing blasts ofair and blasts of steam] through an incandescent fuelbed; and confining the path of movement of all portions of the fuel,during the blasting and process ing thereof within a known,substantially.

uniformly permeable activated area with re spect tol'tClllillllgbounding walls so that formation of inactive masses is therebyprevented, and the entire fuel bed blasted and governed; blasting thebody of fuel sub stantially uniformly with air; and passing steamsubstantially uniformly through the body of fuel whereby initiation ofcentrally located, substantially impermeable fuel masses or cores areeliminated. in the descent through and from the green or loose fuel zoneto the incandescent zone.

the oiftake, down to the zone of incandescence in such columnar formthat all portions of the calumnar fuel body are maintained within a.known, active area and radiating distance relative to the bounding wallsof the columnar fuel body from a point substantially-in line With theofitake to the zone of incandescence; blasting the fuel in a verticaldirection with air; and, alternately with the air blast, blasting withup and down runs of steam, whereby the columnar fuel body is processeduniformly throughout the sectional areas thereof, channeling minimized,and formation of substantially impermeable masses avoided.

5. In the manufacture of gas with an ignited fuel bed and wherein blastsof air and steam are passed through the fuel bed, the improvement forincreasing the output which consists in uniformly distributing theporosity of the fuel bed by co-ordinating the cross sectional area ofthe fuel bed with its bounding surface, in such a way that, thereby, theformation of inactive fuel masses or cores, which would otherwise benormally formed in the fuel bed during blasting is avoided.

6. The herein described improvement in the manufactureof a combustiblegas from solid carbonaceous fuel and wherein the body of fuel gravitatesthrough the generator, which includes: confining the path of movement ofall portions of the fuel during the passage thereof through the zones ofdistillation and incandescence, within a known, substantially uniformlypermeable activated area with respect to radiating wall surfaces bywhich the path of movement of the fuel is determined; blasting the bodyof fuel substantially uniformly with air; and passing' steamsubstantially uniformly through the body of fuel whereby the ratio ofbounding wall surface to the cross section of the body of fuel isthereby increased, the formation of inactive fuel masses or coresprevented, and uniform processing of the fuelbody obtained.

7. The herein described improvement in the manufacture of a combustiblegas of the character described from bituminous coal, and wherein thebody of fuel gravitates through the generator which consists in:confining the path of movement of all portions of the fuel, during thepassage through the zones of distillation and gassification, within adistance of approximately 24 inches or less of a fuel bounding wall;blasting the body of fuel substantially uniformly with steam and withair, the ratio of bounding wall surface to the cross section of thebody'of fuel being thereby increased, formation of inactive fuel massesor cores prevented, and uniform processing of the fuel bed obtained.

In witness that we claim the foregoing we have hereunto subscribed ournames this 16th day of Spetember, 1924.

WILLIS J. MURDOGK. EDGAR n. LUNGREN. ownn B. EVANS.

